<?php
// 水印图的制作
$back = imagecreatefromjpeg('back.jpg');
$logo = imagecreatefromjpeg('logo.jpeg');
// imagecopy($back, $logo, 100, 100, 0, 0, imagesx($logo), imagesy($logo));
// 可以设置透明度copy
imagecopymerge($back, $logo, 50, 30, 0, 0, imagesx($logo), imagesy($logo), 50);
header('Content-type:image/jpeg');
imagejpeg($back);